EC-121 Lockeed Warning Star Vietnam

The EC-121, originally designated RC-121, was a radar-picket version of the U.S. Air Force's C-121 passenger airplane. The EC-121 provided early warning by detecting and tracking enemy aircraft with the electronic gear in the large radomes above and below its fuselage.

The Air Force ordered 82 EC-121s between 1951 and 1955, 72 of which were EC-121Ds. The EC-121 entered service with the Air Defense Command in 1953, flying patrols off the U.S. coasts as an aerial extension of the Distant Early Warning (DEW) Line. EC-121s remained in service until they were replaced by more capable E-3 Sentry AWACS (Airborne Warning And Control System). The last EC-121 was retired from the U.S. Air Force Reserve in 1978.

In Southeast Asia, these unarmed radar aircraft aided in downing enemy planes, directed U.S. aircraft to aerial refueling tankers, and guided rescue planes to downed pilots. EC-121s played a key role by monitoring airborne North Vietnamese MiGs and guiding USAF fighters to intercept them. Orbiting securely outside the border, EC-121 crews used the aircraft's radar and enemy radio communications to detect and locate MiGs within North Vietnamese airspace. These operations began in the spring of 1965 under the code name BIG EYE (later named COLLEGE EYE and DISCO), and continued beyond the end of the war.